Is This a Real Hacking Tool?

Main character, eliot, goes into the main servers of e corp. installs a really simple programme that gives them an easy access door to the server so they can go in. It uses memory, so it's not actually writing anything to disk. This wouldn't olve a simultaneous attack on thousands of things. Would have to involve treasuries as well as mints. I guess, it's a too prolonged attack. There may even be more than that that we just don't understand as viewers, you know, in the world of mister robot.